Substrate processing method and substrate processing apparatus

ABSTRACT

A method for processing a substrate includes: (a) exposing a substrate with a pattern formed on a surface thereof to a first reactive species in a chamber, thereby adsorbing the first reactive species onto the surface of the substrate; (b) exposing the substrate to plasma formed by a second reactive species in the chamber, thereby forming a film on the surface of the substrate; and (c) repeating a processing including (a) and (b) two or more times while changing a residence amount of the first reactive species at a time of starting (b).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority from Japanese PatentApplication Nos. 2019-205415 and 2020-152825, filed on Nov. 13, 2019 andSep. 11, 2020, respectively, with the Japan Patent Office, thedisclosures of which are incorporated herein in their entireties byreference.

TECHNICAL FIELD

The present disclosure relates to a substrate processing method and asubstrate processing apparatus.

BACKGROUND

The atomic layer deposition (ALD) is known as a technique used formanufacturing a semiconductor device. The ALD is classified into a kindof a chemical vapor deposition (CVD). The CVD is a method of forming afilm on a substrate by placing the substrate in a chamber, introducinggases containing components of a film desired to be formed into thechamber, and causing a chemical reaction on the surface of the substrateor in a gas phase state. Unlike the CVD, the ALD does not introduce themultiple reaction gases into the chamber at once. First, the ALDintroduces a first reaction gas (precursor) into the chamber to adsorbthe first reaction gas onto the substrate, and discharges the firstreaction gas that has not been adsorbed from the chamber. Subsequently,the ALD introduces a second reaction gas into the chamber to cause areaction between the second reaction gas and the components of the firstreaction gas adsorbed onto the substrate, thereby forming a film. Sincethe ALD controls the film thickness to an atomic layer level using theself-controllability, the ALD is used for precisely forming a film. See,e.g., US Patent Application Publication No. 2005/0070041.

SUMMARY

According to an aspect of the present disclosure, a method forprocessing a substrate includes: (a) exposing a substrate with a patternformed on a surface thereof to a first reactive species in a chamber,thereby adsorbing the first reactive species onto the surface of thesubstrate; (b) exposing the substrate to plasma formed by a secondreactive species in the chamber, thereby forming a film on the surfaceof the substrate; and (c) repeating a processing including (a) and (b)two or more times while changing a residence amount of the firstreactive species at a time of starting (b).

The foregoing summary is illustrative only and is not intended to be inany way limiting. In addition to the illustrative aspects, embodiments,and features described above, further aspects, embodiments, and featureswill become apparent by reference to the drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart illustrating an example of the flow of a substrateprocessing method according to a first embodiment.

FIG. 2A is a flowchart illustrating the flow of Processing Example 1performed by the substrate processing method according to the firstembodiment.

FIG. 2B is a flowchart illustrating the flow of Processing Example 2performed by the substrate processing method according to the firstembodiment.

FIG. 2C is a flowchart illustrating the flow of Processing Example 3performed by the substrate processing method according to the firstembodiment.

FIG. 2D is a flowchart illustrating the flow of Processing Example 4performed by the substrate processing method according to the firstembodiment.

FIG. 3A is a view illustrating a relationship between a film formingmethod and a coverage.

FIG. 3B is a schematic vertical cross-sectional view of each of patternsthat correspond to (1) to (5) of FIG. 3A.

FIG. 4 is a view illustrating a chemical vapor deposition.

FIG. 5 is a view illustrating an atomic layer deposition.

FIG. 6 is a view illustrating a mix mode in the first embodiment.

FIG. 7 is a view illustrating an example of a configuration of asubstrate processing apparatus according to the first embodiment.

FIG. 8 is a view illustrating an example of processing conditions storedin the substrate processing apparatus according to the first embodiment.

FIG. 9 is a view illustrating an example of processings stored in thesubstrate processing apparatus according to the first embodiment.

FIG. 10 is a view illustrating experimental results of the processingsbased on the substrate processing method according to the firstembodiment.

FIG. 11 is a graph obtained by normalizing each of the experimentalresults illustrated in FIG. 10 .

FIG. 12 is a view illustrating an example of a configuration of asubstrate processing apparatus according to a second embodiment.

FIG. 13 is a view illustrating an example of a configuration ofinformation stored in an association storage unit.

FIG. 14A is a view illustrating an example of a low frequency roughnessof a pattern formed on a substrate.

FIG. 14B is a view illustrating an example of a power spectral densityobtained by measuring the pattern formed on the substrate.

FIG. 14C is a view illustrating an example of a high frequency roughnessof a pattern formed on the substrate.

FIG. 14D is a view illustrating another example of the power spectraldensity obtained by measuring the pattern formed on the substrate.

FIG. 15 is a flowchart illustrating an example of the flow of asubstrate processing method according to the second embodiment.

FIG. 16 is a view illustrating an example of a configuration of aprocessing apparatus in which a substrate processing according to thefirst and second embodiments is performed.

FIG. 17 is a view illustrating an example of a processing system whichis usable for performing the substrate processing according to the firstand second embodiments.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawing, which form a part hereof The illustrativeembodiments described in the detailed description, drawing, and claimsare not meant to be limiting. Other embodiments may be utilized, andother changes may be made without departing from the spirit or scope ofthe subject matter presented here.

Hereinafter, embodiments of the present disclosure will be described indetail based on the accompanying drawings. The embodiments are notlimited. The embodiments may be appropriately combined with each otherwithin a scope that does not cause any inconsistency in processcontents. In the respective drawings, similar or correspondingcomponents will be denoted by the same reference numerals.

In the descriptions herein below, the term “above” indicates thedirection toward the ceiling of a processing apparatus, that is, thedirection of the front surface of a substrate placed in the processingapparatus. The “below” indicates the direction toward the bottom of theprocessing apparatus, that is, the direction of the back surface of thesubstrate placed in the processing apparatus. The terms “upper” and“lower” may be used to indicate a portion of a pattern formed on thesubstrate. An “upper” side indicates the front surface of the substrate,that is, the side of the substrate to be subjected to a processing suchas, for example, film formation or etching. A “lower” side indicates theback surface of the substrate, that is, the side of the substrate whichis not subjected to a processing such as, for example, film formation oretching. The thickness direction of the substrate may be referred to asa vertical direction, and the direction parallel to the surface of thesubstrate may be referred to as a horizontal direction.

In the descriptions herein below, a “reactive species” includes a gascontaining a reactive species.

First Embodiment

FIG. 1 is a flowchart illustrating an example of the flow of a substrateprocessing method according to a first embodiment. The substrateprocessing method according to the first embodiment is executed by asubstrate processing apparatus that controls a processing apparatus(e.g., a chamber) where a processing such as, for example, etching, filmformation or cleaning is performed.

First, the substrate processing apparatus selects one or moreprocessings to be continuously performed on a substrate (e.g., asemiconductor substrate formed of silicon) (step S11). Subsequently, thesubstrate processing apparatus causes the processing apparatus toperform the selected processings (step S12). When the performance of theprocessings is completed, the processings end.

Here, the “processing” includes one or more processings performed on thesubstrate. The one or more processings are, for example, a filmformation, an etching, a cleaning, and a temperature controlling.Further, the “processing” includes information about an order ofperforming the one or more processings.

FIGS. 2A to 2D are flowcharts illustrating the flows of ProcessingExamples 1 to 4 performed by the substrate processing method accordingto the first embodiment.

Processing Example 1 illustrated in FIG. 2A is a film formationprocessing by the CVD. First, the substrate processing apparatus causesa reaction between a first reactive species and a second reactivespecies in a chamber, to form a film on the surface of the substrate(step SA1). Then, the substrate processing apparatus ends theprocessing.

Processing Example 2 illustrated in FIG. 2B is a film formationprocessing by the ALD (including a “mix mode” to be described later).The processing of Processing Example 2 includes steps “a” and “b.” Instep “a,” the substrate processing apparatus exposes the substrate witha pattern formed on the surface thereof to the first reactive species inthe chamber, so as to adsorb the first reactive species onto the surfaceof the substrate (step SB1). Subsequently, in step “b,” the substrateprocessing apparatus exposes the substrate to plasma formed from thesecond reactive species in the chamber, so as to form a film on thesurface of the substrate (step SB2). The substrate processing apparatusdetermines whether a predetermined number of cycles have been performed(step SB3). When it is determined that the predetermined number ofcycles have not been performed (steps SB3, No), the substrate processingapparatus returns to step SB1, and repeats the processing. Meanwhile,when it is determined that the predetermined number of cycles have beenperformed (step SB3, Yes), the substrate processing apparatus ends theprocessing.

As illustrated in FIG. 2B, step “a” may include step a1 of adsorbing thefirst reactive species onto the substrate and step a2 of purging atleast a portion of the first reactive species from the chamber.Similarly, step “b” may include step b1 of introducing the secondreactive species into the chamber to form plasma and form a film, andstep b2 of purging at least a portion of the second reactive speciesfrom the chamber.

Processing Example 3 illustrated in FIG. 2C is an etching. First, thesubstrate processing apparatus performs an etching (step SC1). Then, thesubstrate processing apparatus ends the processing.

Processing Example 4 illustrated in FIG. 2D is a processing in which afilm formation and an etching are combined with each other underdifferent conditions. Processing Example 4 is a processing of performingProcessing Examples 1, 2, and 3 in an order. The substrate processingapparatus first performs Processing Example 1 (step SD1). Subsequently,the substrate processing apparatus performs Processing Example 2 (stepSD2). Subsequently, the substrate processing apparatus performsProcessing Example 3 (step SD3). Then, the substrate processingapparatus ends the processing.

Further, the “processing” includes information about a processingcondition of each processing. The information about a processingcondition includes, for example, a pressure in the chamber, a frequencyand a power of a radio frequency applied for generating plasma, a typeand a flow rate of a gas, a processing time, and a temperature of eachunit of the chamber. Further, the “processing” includes informationabout the number of times of performing each processing and the numberof times of repeating a plurality of processings in a predeterminedorder. For example, when a plurality of cycles is performed inProcessing Example 2 illustrated in FIGS. 2A to 2D, different processingconditions may be set for the cycles. The “processing” performed by thesubstrate processing method according to the first embodiment includesone or more processings that implement a film formation with differentcoverages, for example, on a pattern having a height difference on thesubstrate.

Here, the “coverage” refers to a ratio of a film formed on the upperportion of the pattern having the height difference on the substrate toa film formed on the lower portion of the pattern. The coverage refersto, for example, a ratio of the film thickness of a film formed on theupper portion of the inner periphery of a hole formed in the substrateto the film thickness of a film formed on the lower portion of the innerperiphery of the hole. Further, for example, the coverage refers to aratio of the film thickness of a film formed on the surface of thesubstrate to the film thickness of a film formed on the bottom surfaceof a hole formed in the substrate. For example, in the film formationprocessing using the CVD, a film is mainly formed on the upper portionof the pattern. Meanwhile, in the film formation processing using theALD, a film is constantly formed on the surface of the substrate,regardless of the height difference of the pattern. In this way, thecoverage changes according to the film forming method.

FIG. 3A is a view illustrating a relationship between the film formingmethod and the coverage. In the graph of FIG. 3A, the horizontal axisrepresents a vertical position in a pattern formed on the substrate, forexample, a hole (referred to as an aspect ratio herein). The verticalaxis represents the film thickness of a film formed on the pattern. Forexample, the graph (1) represents a state where the film thickness of afilm formed on a position with a relatively low aspect ratio, that is,the upper portion of the pattern is relatively large, and no film isformed on a position with a relatively high aspect ratio, that is, thelower portion of the pattern. The graphs (2) to (4) represent a statewhere the film thickness of a formed film gradually decreases from theupper portion toward the lower portion of the pattern. The graph (5)represents a state where the film thickness of a formed film issubstantially uniform over the upper portion to the lower portion of thepattern.

FIG. 3B is a schematic vertical cross-sectional view of each of thepatterns that correspond to (1) to (5) of FIG. 3A. In FIG. 3B, thepattern (1) represents a state where a film F is formed only on the topTop of a pattern P. In FIG. 3B, the patterns (2) to (4) represent astate where the film formation amount gradually changes over the topTop, the upper portion of the side wall SW, and the lower portion of theside wall SW of the pattern P. In FIG. 3B, the pattern (5) represents astate where the film F is formed with the substantially uniformthickness over the top Top, the upper portion of the side wall SW, thelower portion of the side wall SW, and the bottom BT of the pattern P.In FIG. 3B, the patterns (1) to (5) substantially correspond to thegraphs (1) to (5) of FIG. 3A, respectively.

Next, each of the methods for implementing the coverages of (1) to (5)of FIGS. 3A and 3B will be described.

FIG. 4 is a view illustrating the CVD. In the CVD, gases containingcomponents that react with each other to form a film are introduced intothe chamber in which the substrate is placed, and a film is formed onthe substrate by the reaction. In the example of FIG. 4 , gases A and Bare simultaneously introduced into the chamber in which a substrate Sub((A) of FIG. 4 ) is placed. The reactive species of the introduced gas Aand the reactive species of the introduced gas B react with each otherto form a film on the substrate Sub ((B) of FIG. 4 ). The components ofthe film that have reacted with each other in the gas phase state aredeposited from above. Accordingly, when a pattern having a heightdifference exists on the substrate, the coverage of the film formed bythe CVD decreases from the upper portion toward the lower portion of thepattern.

FIG. 5 is a view illustrating the ALD. In the ALD, a film is formed bysequentially introducing the first reactive species and the secondreactive species into the chamber in which the substrate is placed. Inthe example of FIG. 5 , the gas A (the first reactive species) is firstintroduced into the chamber in which the substrate Sub ((A) of FIG. 5 )is placed ((B) of FIG. 5 ). The molecules of the gas A are adsorbed ontothe surface of the substrate Sub ((C) of FIG. 5 ). When there is no moresite onto which the molecules of the gas A are to be adsorbed, themolecules of the gas A are no longer deposited on the substrate Sub. Thegas A remaining in the chamber is purged. Subsequently, the gas B (thesecond reactive species) is introduced into the chamber ((D) of FIG. 5). At this time, plasma may be generated from the gas B to promote thereaction. The molecules or radicals of the gas B react with themolecules adsorbed onto the substrate Sub to form a film. At this time,when all of the molecules of the gas A on the substrate Sub react withthe molecules of the gas B, the remaining molecules of the gas B residein the gas phase state in the chamber. Then, the residing gas B ispurged ((E) of FIG. 5 ). In this way, in the ALD, the film is formed byperforming the four steps of adsorption, purging, reaction (e.g.,oxidation), and purging. Since the ALD implements the film formation inthe self-controlled manner, the coverage of the film formed by the ALDimplements the substantially uniform film thickness over the upperportion to the lower portion of the pattern.

FIG. 6 is a view illustrating the mix mode in the first embodiment. Inthe first embodiment, the “mix mode” refers to causing the reactionbetween the first reactive species A and the second reactive species Bin the gas phase state as in the CVD, while using the same processingflow as that in the ALD, in other words, refers to a film forming methodin which the ALD and the CVD are combined with each other.

In the example of FIG. 6 , first, the gas A (the first reactive species)is introduced into the chamber in which the substrate Sub ((A) of FIG. 6) is placed. The molecules of the introduced gas A are adsorbed onto thesubstrate Sub ((B) of FIG. 6 ). In the mix mode, the gas A is notcompletely purged from the chamber after the molecules of the gas A areadsorbed onto the substrate Sub ((C) of FIG. 6 ). Then, the gas B (thesecond reactive species) is introduced into the chamber in which the gasA remains ((D) of FIG. 6 ). The molecules of the gas B react with themolecules of the gas A adsorbed onto the substrate Sub, andsimultaneously, react with the molecules of the gas A that exist in thegas phase state in the chamber, so as to form a film. As a result, inaddition to the film formed in the self-controlled manner in the ALD,the film having the same coverage as that in the CVD is formed ((E) ofFIG. 6 ). The gas A is, for example, a silicon-containing gas. The gas Bis, for example, an oxygen-containing gas. Further, for example, acarbon-containing gas may be used as the gas A. Further, for example, anitrogen-containing gas may be used as the gas B.

In the film formation by the mix mode, the coverage may be changed byadjusting the amount of the first reactive species that remain in thechamber (hereinafter, also referred to as the residence amount) when thesecond reactive species is introduced into the chamber. The coverage inthe mix mode may be adjusted by the following processing conditions:

(1) Processing time for the step of purging the first reactive species(step (C) of FIG. 6 )

(2) Pressure in the chamber in the step of purging the first reactivespecies

(3) Flow rate of a purging gas used for the step of purging the firstreactive species

(4) Dilution degree of the first reactive species (step (B) of FIG. 6 )

Here, the time required to replace a gas in the chamber (hereinafter,also referred to as the residence time) may be expressed by thefollowing equation:T=(P×V)/(Q)  (1)

In the equation, the symbol “T” refers to the residence time (second),that is, the time during which a gas resides in the processing space(the chamber). The symbol “P” refers to the pressure (Torr) in theprocessing space. The symbol “V” refers to the volume (liter) of theprocessing space. The symbol “Q” refers to the flow rate (sccm) of thegas. As seen from the equation (1), the residence time T is proportionalto the volume of the processing space and the pressure in the processingspace, and is inversely proportional to the flow rate of a gas.Accordingly, as the volume of the processing space is relatively large,and the pressure in the processing space is relatively high, theresidence time becomes relatively long. Further, as the flow rate of agas is relatively large, the residence time becomes relatively short.

Accordingly, the amount of the first reactive species that remains inthe chamber may be increased when the second reactive species isintroduced into the chamber, by adjusting the processing conditions asfollows:

(1) Reduce the processing time for the step of purging the firstreactive species (e.g., making the processing time shorter than theresidence time)

(2) Increase the pressure in the chamber during the step of purging thefirst reactive species

(3) Reduce the flow rate of the purging gas used for the step of purgingthe first reactive species

In a case where the processing conditions for the step of purging thefirst reactive species are not changed, the residence amount of thefirst reactive species may also be increased by increasing the dilutiondegree of the first reactive species (the processing condition (4)above) so as to increase the amount of the reactive molecules thatreside without being adsorbed onto the substrate. Further, the residenceamount of the first reactive species may be maintained by not performingthe purging step.

As described above, in the substrate processing method according to thefirst embodiment, the film formation processings that implementdifferent coverages are combined with each other, so that the continuouscoverage control is implemented.

(Example of Configuration of Substrate Processing Apparatus)

FIG. 7 is a view illustrating an example of a configuration of asubstrate processing apparatus 100 according to the first embodiment.The substrate processing apparatus 100 may be configured by aninformation processing apparatus such as, for example, a personalcomputer (PC). The substrate processing apparatus 100 is connected to aprocessing apparatus 200 via a network NW.

The network NW may be, for example, the Internet, an intranet, a localarea network, a wide area network or a combination thereof. Further, thenetwork NW may be a wired network, a wireless network or a combinationthereof.

The processing apparatus 200 includes the processing space (the chamber)where a processing is performed on the substrate, and performs theprocessing on the substrate. The details of the processing apparatus 200will be described later. The configuration and the type of theprocessing apparatus 200 are not particularly limited. The processingapparatus 200 may be, for example, any plasma processing apparatus usinga plasma source such as, for example, capacitively coupled plasma (CCP),inductively coupled plasma (ICP) or microwave plasma. The processingapparatus 200 performs, for example, the film formation such as theatomic layer deposition (ALD) or the chemical vapor deposition (CVD),and the etching. The processing apparatus 200 may or may not use plasmafor the processing on the substrate.

The substrate processing apparatus 100 includes a storage unit 110, acontroller 120, an input unit 130, an output unit 140, and acommunication unit 150.

The storage unit 110 stores information used for a processing in thesubstrate processing apparatus 100 and information generated as a resultof the processing. Examples of the storage unit 110 include a flashmemory, a random access memory (RAM), a read only memory (ROM), a harddisk, and an optical storage device.

The controller 120 controls the operation and the functions of thesubstrate processing apparatus 100. The controller 120 is, for example,an integrated circuit or an electronic circuit. Examples of thecontroller 120 include a central processing unit (CPU) and a microprocessing unit (MPU).

The input unit 130 receives an input of information from the outside tothe substrate processing apparatus 100. Examples of the input unit 130include a touch panel, a mouse, a keyboard, a microphone, and peripheralcircuits thereof

The output unit 140 outputs information from the substrate processingapparatus 100. Examples of the output unit 140 include a screen, aspeaker, a printer, and peripheral circuits thereof.

The communication unit 150 implements a communication with other devicesthrough the network NW. Examples of the communication unit 150 include amodem, a port, a router, and a switch.

(Information Stored in Storage Unit 110)

The storage unit 110 includes a processing condition storage unit 111and a processing storage unit 112.

The processing condition storage unit 111 stores processing conditionsfor processings performed on the substrate in the processing apparatus200, for example, the film formation and the etching.

FIG. 8 is a view illustrating an example of the processing conditionsstored in the substrate processing apparatus 100 according to the firstembodiment. The processing conditions are, for example, the processingconditions for each film formation processing described above withreference to FIGS. 4 to 6 . For example, in the CVD, the processingconditions include, for example, the pressure in the chamber, thefrequency and the power of the radio frequency HP applied when plasma isgenerated, the type of a gas introduced into the chamber, and the flowrate (ratio) of the gas. The processing conditions also include theprocessing time and a set temperature of each unit of the chamber. Inthe ALD and the mix mode, the processing conditions may be set for eachof the step of adsorbing the first reactive species (step a1), the stepof pursing the first reactive species (step a2), and the step of causingthe reaction of the second reactive species (step b1), and the step ofpurging the second reactive species (step b2). FIG. 2B illustrates thesteps a1, a2, b1, and b2.

In the example of FIG. 8 , the processing conditions include “ConditionID (Identifier),” “Step No.” “Pressure,” “Radio Frequency (HP),” “Gas,”“Flow Rate,” “Processing Time,” and “Temperature.” “Condition ID”represents an identifier that uniquely identifies each processingcondition. “Step No.” represents a number that identifies each step whenone processing includes a plurality of steps. “Pressure” represents apressure value in the chamber during the processing. “Radio Frequency(HP)” represents the frequency and the power of a radio frequencyapplied to an electrode in the chamber during the processing. “Gas”represents information that specifies a gas to be introduced into thechamber during the processing. “Flow Rate” represents the flow rate ofthe corresponding gas. “Processing Time” represents the time for theprocessing. “Temperature” represents the temperature of a predeterminedunit of the chamber that is set when the processing is performed.

For example, in FIG. 8 , Step Nos. “1” to “4” are stored in theprocessing condition identified by “Condition ID: P100.” This indicatesthat the processing condition specified by Condition ID “P100” includesfour steps. Further, “Pressure: XXmT,” “Gas: X/Y,” “Flow Rate: R1/R2,”“Processing Time: 2 sec,” and “Temperature: T1/T2/T3” are stored inassociation with “Step No.: 1.” This indicates that the pressure of thechamber is set to XXmT during the step specified by Step No. “1” in theprocessing condition of Condition ID “P100.” Further, it indicates thatan X gas (an unspecified gas here) and a Y gas are supplied into thechamber at the flow rate ratio of R1 sccm to R2 sccm in the step.Further, it indicates that the processing time of the step is 2 seconds.Further, it indicates that the temperature of a predetermined unit ofthe chamber is set to T1 ° C., T2 ° C., and T3 ° C. during theperformance of the step.

In FIG. 8 , the processing condition represented by Condition ID “P100”corresponds to the ALD. In the processing condition of Condition ID“P100,” Step No. “1” represents the processing condition of theadsorption step (step a1), and Step No. “2” represents the processingcondition of the purging step (step a2) after the adsorption step. StepNo. “3” represents the processing condition of the reaction step (stepb1), and Step No. “4” represents the processing condition of the purgingstep (step b2) after the reaction step. In FIG. 8 , the processingcondition represented by Condition ID “P200” corresponds to the CVD (seestep SA1 of FIG. 2A). Since the processing of Condition ID “P200”includes one step, only the processing condition of Step No. “1” isstored. In FIG. 8 , the processing conditions represented by ConditionIDs “P301” to “P303” correspond to the mix mode. The processingconditions of Condition IDs “P301” to “P303” are substantially similarto the processing condition of Condition ID “P100,” except for the“Processing Time” of Step No. “2.” This is because the processingconditions of Condition IDs “P301” to “P303” set the processing time ofthe purging step (step a2) to be relatively short, in order to implementthe mix mode.

The processing storage unit 112 stores a processing which is acombination of the processing conditions stored in the processingcondition storage unit 111.

FIG. 9 is a view illustrating an example of the processings stored inthe substrate processing apparatus 100 according to the firstembodiment. In the example of FIG. 9 , each processing includes“Processing ID,” “Number of Cycles,” and “Condition ID/Procedure.”“Processing ID” represents an identifier that uniquely identifies aprocessing. “Number of Cycles” represents the number of times ofpreforming the processing based on a processing condition thatcorresponds to the processing. “Condition ID/Procedure” represents aprocessing condition for performing the processing, and the procedure ofperforming the processing when a plurality of processings is performed.Further, “Condition ID/Procedure” may be information about a processingID and a procedure, instead of the condition ID and the procedure.

For example, in the example of FIG. 9 , “Number of Cycles: 1” and“Condition ID/Procedure: P200” are stored in association with“Processing ID: S001.” This indicates that the processing specified byProcessing ID “S001” is performed once based on the processing conditionspecified by Condition ID “P200.” The processing condition specified byCondition ID “P200” is stored in the processing condition storage unit111. That is, the processing condition of Condition ID “P200” representsthe chamber pressure “XXmT,” the radio frequency HP “Z1MHz/Z2W,” the gas“X/Y,” and the flow rate “R1/R2.” The processing time is “10 sec,” andthe temperature is “T1/T2/T3.”

For example, in the example of FIG. 9 , “Number of Cycles: 5” andCondition ID/Procedure: S001→S003→S100″ are stored in association withProcessing ID “S500.” This indicates that for the processing specifiedby Processing ID “S500,” processings specified by Processing IDs “S001,”“S003,” and “S100,” respectively, are performed in this order. Further,it indicates that the three processings are repeated five times in anorder. The processing specified by

Processing ID “S001” is the CVD, and the processing specified byProcessing ID “S003” is the mix mode (see FIG. 8 ). When the processingspecified by Processing ID “S100” is the etching, Processing ID “S500”represents that the CVD, the ALD, and the etching are continuously andrepeatedly performed five times.

(Configuration and Functions of Controller 120)

Referring back to FIG. 7 , the configuration and the functions of thecontroller 120 will be described. The controller 120 includes aselection unit 121 and an instruction unit 122.

The selection unit 121 receives an instruction input through the inputunit 130 or the communication unit 150. Then, the selection unit 121selects one or more processings that correspond to the receivedinstruction, from the storage unit 110 (step S11 of FIG. 1 ). Theselection unit 121 sends the selected processings to the instructionunit 122.

The instruction unit 122 instructs the processing apparatus 200 toperform processings based on the processings selected by the selectionunit 121 (step S12 of FIG. 1 ).

(Experimental Examples)

FIG. 10 is a view illustrating experimental results of processings basedon the substrate processing method according to the first embodiment. InFIG. 10 , (A) illustrates a coverage obtained when the CVD is performedonce for 10 seconds based on Processing ID “S001” (see FIGS. 8 and 9 ).In FIG. 10 , (B) illustrates a coverage obtained when the processingbased on Processing ID “S002” (see FIGS. 8 and 9 ) in which the purgingtime in the mix mode is set to 0.5 seconds is performed 40 times. InFIG. 10 , (C) illustrates a coverage obtained when the processing basedon Processing ID “S003” (see FIGS. 8 and 9 ) in which the purging timein the mix mode is set to 0.7 seconds is performed 70 times. In FIG. 10, (D) illustrates a coverage obtained when the processing based onProcessing ID “S004” (see FIGS. 8 and 9 ) in which the purging time inthe mix mode is set to 1 second is performed 105 times. In FIG. 10 , (E)illustrates a coverage obtained when the ALD is performed 200 timesbased on Processing ID “S005” (see FIGS. 8 and 9 ).

The processing conditions of Condition IDs “P301,” “P302,” “P303,” and“P100” are different from each other only in length of the time forpurging the first reactive species. In FIG. 10 , the purging time is 0.5seconds for (B), 0.7 seconds for (C), 1 second for (D), and 10 secondsfor (E), which gradually increase from (B) toward (E). Thus, theresidence amount of the first reactive species (an X-containing gas inthe example of FIG. 10 ) when the second reactive species (anoxygen-containing gas in the example of FIG. 10 ) is introduced into thechamber decreases from (B) toward (E). Thus, it is understood that thefilm formation amount in the CVD method is the largest in (B), anddecreases from (C) toward (D). Further, it is understood that the filmformation of the ALD method is implemented in (E).

In the example of (A) of FIG. 10 , the film is generally formed on thetop portion of the pattern, and is not substantially formed on the lowerportion of the pattern. That is, the coverage that corresponds to (1) ofFIG. 3B is implemented under the processing condition of (A) of FIG. 10.

In the example of (B) of FIG. 10 , the film thickness graduallydecreases from the upper portion toward the lower portion of thepattern, and the film is not substantially formed on the lower portionof the pattern. That is, the coverage that substantially corresponds to(2) of FIG. 3B is implemented under the processing condition of (B) ofFIG. 10 .

In the example of (C) of FIG. 10 , the film thickness of the formed filmbecomes larger as a whole than (B), and decreases from the upper portiontoward the lower portion of the pattern as in (B). That is, it may besaid that (C) of FIG. 10 generally corresponds to (3) of FIG. 3B.

In the example of (D) of FIG. 10 , the film thickness of the formed filmbecomes further larger than (C), and the film is also formed at thebottom of the pattern. It may be said that (D) of FIG. 10 implements thecoverage that substantially corresponds to (4) of FIG. 3B.

In the example of (E) of FIG. 10 , the film thickness of the formed filmhas no substantial difference between the upper portion and the lowerportion of the pattern, and a substantially uniform film is formed. Thatis, the coverage that corresponds to (5) of FIG. 3B is implemented underthe processing condition of (E) of FIG. 10 .

In the graphs of FIG. 10 , the “Depth” represents a distance (dimension)from the upper end to the lower end of the film formed on the side wall.That is, the “Depth” represents a dimension that does not include thetop and the bottom (corresponding to the dimension indicated by D1 inFIG. 10 ). The “D/A” represents the thickness of the film formed on theside wall.

FIG. 11 represents graphs obtained by normalizing the experimentalresults illustrated in FIG. 10 . As seen from FIG. 11 , the coveragegradually changes from (A) through (E), and an intermediate film formingmethod between the CVD and the ALD is implemented. Thus, according tothe substrate processing method of the first embodiment, the filmformation with a desired coverage may be implemented by continuouslychanging the coverage.

In the ALD, a conformal film may not be necessarily formed. For example,the adsorption position of the first reactive species may be limited tothe upper portion of the pattern, such that the film is formed only onthe upper portion of the pattern. Further, the processing may beterminated before the second reactive species reaches the bottom of thepattern, such that the film is formed only on the upper portion of thepattern. The coverage may be more flexibly controlled by using asubconformal ALD.

(Effects of First Embodiment)

As described above, the substrate processing method according to thefirst embodiment includes steps “a,” “b,” and “c.” Step “a” exposes thesubstrate with a pattern formed on the surface thereof to the firstreactive species in the chamber, so as to absorb the first reactivespecies onto the surface of the substrate. Step “b” exposes thesubstrate to plasma formed from the second reactive species in thechamber, so as to form a film on the surface of the substrate. Step “c”repeats the processing including steps “a” and “b” two or more times bychanging the residence amount of the first reactive species at the timeof starting step “b.” As a result, according to the substrate processingmethod of the first embodiment, the coverage of the film formed on thesubstrate may be continuously controlled. For example, as the residenceamount of the first reactive species at the time of starting step “b” isrelatively large, the thickness of the film formed on the upper portionof the pattern becomes thicker than the thickness of the film formed onthe lower portion of the pattern. Meanwhile, as the residence amount ofthe first reactive species at the time of starting step “b” isrelatively small, the thickness of the film formed on the upper portionof the pattern becomes similar to the thickness of the film formed onthe lower portion of the pattern. As a result, according to thesubstrate processing method of the first embodiment, the coverage of thefilm formed on the substrate may be continuously controlled depending onthe residence amount of the first reaction species at the time ofstarting step “b.”

In the substrate processing method according to the first embodiment,the residence amount of the first reactive species at the time ofstarting step “b” may be changed by controlling the amount of the firstreactive species introduced into the chamber in step “a.” Further, inthe substrate processing method according to the first embodiment, theresidence amount of the first reactive species at the time of startingstep “b” may be changed by controlling the dilution degree of the firstreactive species introduced into the chamber in step “a.” As a result,according to the first embodiment, the coverage of the film formed onthe substrate may be easily controlled by adjusting the amount or thedilution degree of the first reactive species.

In the substrate processing method according to the first embodiment,step “a” may include step al of introducing the first reactive speciesinto the chamber, and step a2 of purging at least a portion of the firstreactive species from the chamber. In the substrate processing methodaccording to the first embodiment, the residence amount of the firstreactive species at the time of starting step “b” may be changed bycontrolling the amount of the first reactive species purged in step a2.As a result, according to the first embodiment, the amount of the firstreactive species in the chamber may be adjusted in the purging step. Asa result, according to the first embodiment, the coverage of the filmformed on the substrate may be continuously controlled by simplyadjusting the processing condition. Further, according to the firstembodiment, an intermediate film forming method between the ALD and theCVD may be easily implemented by changing the processing condition ofthe purging step.

In the substrate processing method according to the first embodiment,the amount of the first reactive species at the time of starting step“b” may be changed by changing the residence amount of the firstreactive species purged in step a2 in the manner of changing at leastone of the pressure in the chamber, the processing time, and the flowrate of the purging gas. As a result, according to the first embodiment,the coverage of the film formed on the substrate may be controlled byselecting and adjusting an easily controllable condition among theplurality of processing conditions

In the substrate processing method according to the first embodiment,step “a” or “b” may be terminated before the reaction on the substratesurface is saturated. As a result, in the substrate processing methodaccording to the first embodiment, the coverage of the film formed onthe substrate may be further finely adjusted by using the subconformalALD.

In the substrate processing method according to the first embodiment mayfurther include step “d” of etching the substrate using the film formedin step “c” as a mask (protective film), after step “c.” In thesubstrate processing method according to the first embodiment, step “c”may be repeatedly performed until the shape of the pattern satisfies apredetermined condition. The substrate processing method according tothe first embodiment may further include step “e” of repeatedlyperforming a processing including steps “c” and “d” two or more times.As a result, according to the first embodiment, the etching may beperformed after the shape of the mask is corrected by continuouslycontrolling the coverage. As a result, according to the firstembodiment, the etching accuracy may be improved. Further, according tothe first embodiment, the etching may be performed while correcting theshape of the mask.

In the substrate processing method according to the first embodiment,step “c” may be performed in the same chamber. As a result, according tothe first embodiment, the throughput of the processing may be furtherimproved. When the substrate processing method according to the firstembodiment includes step “d,” steps “c” and “d” may be performed in thesame chamber or in different chambers. As a result, according to thefirst embodiment, the entire substrate processing may be optimized whilebalancing the film formation time and the etching time.

In the substrate processing method according to the first embodiment,step “c” may be performed by setting the pressure in the chamber toabout 10 mTorr to about 200 mTorr. While the residence time is reducedwhen the pressure is set to be relatively low, the mix mode according tothe first embodiment may be implemented by adjusting the otherprocessing conditions. As a result, according to the first embodiment,the throughput of the substrate processing may be improved whilesuppressing the increase in processing time.

The substrate processing apparatus according to the first embodimentincludes the selection unit and the instruction unit. The selection unitselects a plurality of processings. The processing includes, forexample, steps “a,” “b,” and “c.” Step “a” exposes the substrate with apattern formed on the surface thereof to the first reactive species inthe chamber, so as to absorb the first reactive species onto the surfaceof the substrate. Step “b” exposes the substrate to plasma formed fromthe second reactive species in the chamber, so as to form a film on thesurface of the substrate. Step “c” repeats the processing includingsteps “a” and “b” two or more times while changing the residence amountof the first reactive species at the time of starting step “b.” In step“c,” the plurality of processings selected by the selection unit aredifferent from each other in residence amount of the first reactivespecies at the time of starting step “b.” The instruction unit instructsthe performance of the plurality of processings selected by theselection unit in the chamber. As a result, according to the substrateprocessing apparatus of the first embodiment, the coverage of the filmformed on the substrate may be continuously controlled.

Second Embodiment

In the substrate processing apparatus according to the first embodiment,the processing conditions are set in advance, and a processing isselected in accordance with the coverage desired to be achieved. In asubstrate processing apparatus according to a second embodiment, aprocessing is selected and performed in accordance with the state of thepattern on the substrate. In a substrate processing method according tothe second embodiment, a processing is selected and performed inaccordance with, for example, a degree of roughness of a pattern on thesubstrate.

FIG. 12 is a view illustrating an example of a configuration of asubstrate processing apparatus 100A according to the second embodiment.The configuration of the substrate processing apparatus 100A accordingto the second embodiment is substantially similar to that of thesubstrate processing apparatus 100 according to the first embodiment.The substrate processing apparatus 100A is different from the substrateprocessing apparatus 100 in that the substrate processing apparatus 100Aincludes an association storage unit 113 and an acquisition unit 123.Further, the substrate processing apparatus 100A is different from thesubstrate processing apparatus 100 in that the substrate processingapparatus 100A is connected for communication to a measuring apparatus300 via the network NW. Among the components of the substrate processingapparatus 100A, the components similar to those of the substrateprocessing apparatus 100 will not be described, and the differentcomponents will be described below.

The substrate processing apparatus 100A is connected for communicationto the processing apparatus 200 and the measuring apparatus 300 via thenetwork NW. The network NW and the processing apparatus 200 are similarto the network NW and the processing apparatus 200 of the firstembodiment (see FIG. 7 ).

The measuring apparatus 300 measures the shape of the pattern formed onthe substrate, and outputs a value that represents the shape. The valueoutput by the measuring apparatus 300 may be referred to as a measuredvalue. The type of the measured value that is output by the measuringapparatus 300 is not particularly limited. The measured value may be,for example, an aspect ratio of the pattern formed on the substrate. Themeasured value may be, for example, a standard deviation of a signalwaveform that represents the unevenness of the pattern formed on thesubstrate. The measured value may be, for example, a power spectraldensity (PSD) of the signal waveform that represents the unevenness ofthe pattern formed on the substrate. Since the same standard deviationmay be obtained even when the period of unevenness is entirelydifferent, it may be preferable to use the power spectral density as themeasured value in order to improve the measurement accuracy (see“Reducing Roughness in Extreme Ultra Violet Lithography,” Chris A. Mack,Journal of Micro/Nanolithography, MEMS and MOEMS, 17(4), 041006(2018)).In the second embodiment, the measured value may include at least theaspect ratio and the power spectral density.

For example, the measuring apparatus 300 may be an apparatus thatderives, for example, the standard deviation and the power spectraldensity of the pattern shape based on information and images obtained byanalyzing the pattern formed on the substrate using a scanning electronmicroscope (SEM). In the example of FIG. 12 , it is assumed that thesubstrate processing apparatus 100A and the measuring apparatus 300 areconnected to each other through the network NW. The measuring apparatus300 may not be connected to the substrate processing apparatus 100 A,and a measured value separately derived by an operator or the like maybe input to the substrate processing apparatus 100 A.

The substrate processing apparatus 100 A includes a storage unit 110 A,a controller 120 A, an input unit 130, an output unit 140, and acommunication unit 150.

The storage unit 110 A includes the association storage unit 113, inaddition to the processing condition storage unit 111 and the processingstorage unit 112 which are similar to those in the first embodiment. Theassociation storage unit 113 stores an association between the measuredvalue that is input from the measuring apparatus 300, and a processing.

FIG. 13 is a view illustrating an example of a configuration ofinformation stored in the association storage unit 113. In the exampleof FIG. 13 , the association storage unit 113 stores “Device ID,”“Measured Value: Aspect Ratio, PSD,” and “Processing ID.” “Device ID”represents information that specifies a device formed by a processing.Further, “Device ID” may be information that represents an aspect ratioand a target value of PSD. “Measured Value: Aspect Ratio” represents anaspect ratio of a pattern that is obtained by measuring a pattern formedon the substrate. “Measured Value: PSD” represents a power spectraldensity of a pattern that is obtained by measuring a pattern formed onthe substrate. “Processing ID” represents a processing applied to apattern of a corresponding “Measured Value” in order to achieve acorresponding “Device ID.”

FIGS. 14A to 14D are views illustrating a relationship between the powerspectral density and the pattern shape. FIG. 14A is a view illustratingan example of a low frequency roughness of a pattern formed on thesubstrate. FIG. 14B is a view illustrating an example of the powerspectral density obtained by measuring the pattern formed on thesubstrate.

Here, the low frequency roughness refers to a roughness, that is,unevenness that occurs in a relatively large period, as compared with ahigh frequency roughness, and the high frequency roughness refers to aroughness that occurs in a relatively small period, as compared with thelow frequency roughness.

In FIG. 14A, (1) illustrates a state where an unevenness occurs in awave shape in a line-and-space pattern that is originally formed in alinear shape. FIG. 14A is a view of the pattern when viewed from top tobottom. In the example of (1) of FIG. 14A, the space between linesdiffers in X1 and X2. The power spectral density obtained by measuringthe pattern of (1) of FIG. 14A may be represented as illustrated in (1)of FIG. 14B. In the graph of FIG. 14B, the horizontal axis representsthe frequency (unit: nanometer [nm]), and the vertical axis representsthe power spectral density (unit: nm³), in other words, the magnitude ofenergy in each frequency band. In the graph of FIG. 14B, the roughnessthat occurs in a relatively small period, that is, the high frequencyroughness increases toward the right side of the horizontal axis, andthe roughness that occurs in a relatively large period, that is, the lowfrequency roughness increases toward the left side of the horizontalaxis.

Here, the roughness of the pattern of (1) in FIG. 14A is improved byflattening the unevenness ((2) of FIG. 14A). In the example of (2) ofFIG. 14A, the space between lines becomes uniform, and the portion X1 in(1) becomes the space X3 that is substantially equal to the otherportions. Then, the shape of the graph of the power spectral densityalso changes. In FIG. 14B, (2) is an example of the power spectraldensity obtained by measuring the pattern with the improved roughness.In FIG. 14B, (2) represents that the low frequency roughness, that is,the roughness that occurs in a relatively large period is improved, andthe pattern surface is flattened.

FIG. 14C is a view illustrating an example of the high frequencyroughness of the pattern formed on the substrate. FIG. 14D is a viewillustrating another example of the power spectral density obtained bymeasuring the pattern formed on the substrate.

In FIG. 14D, (1) represents the pattern with the high frequencyroughness illustrated in (1) of FIG. 14C, using the power spectraldensity. At this time, the roughness of the pattern of (1) in FIG. 14Cis improved by flattening the unevenness ((2) of FIG. 14C). Then, theshape of the graph changes as illustrated in (2) of FIG. 14D. Form (2)of FIG. 14D, it may be understood that the high frequency roughness isimproved, as compared with the low frequency roughness, and the patternsurface is flattened.

The low frequency roughness illustrated in FIG. 14B may be flattened by,for example, the CVD. Since the film formed by the CVD tends to bedeposited in a relatively large void, the film fills up a concaveportion having a relatively large low frequency roughness.

In the high frequency roughness illustrated in FIG. 14D, the size of theconcave portion that causes the roughness is relatively small in view ofthe entire pattern. Thus, the concave portion may not be preferentiallyfilled up in the film formation by the CVD. Accordingly, in order toimprove the high frequency roughness, it is preferable to use the mixmode in which the ALD and the CVD are combined with each other.

In the substrate processing method according to the second embodiment,the shape of the pattern on the substrate to be processed such as theroughness is measured before a processing is performed, and a processingcondition to be adopted, that is, a processing is selected according tothe measured value. As a result, a processing may be selected inaccordance with a shape abnormality that occurs in the pattern on thesubstrate, and the pattern shape may be corrected.

In the descriptions above, an example where either the CVD or the mixmode is selected according to the roughness of the pattern on thesubstrate has been described. However, the substrate processing methodaccording to the second embodiment is not limited thereto. For example,a first threshold value and a second threshold value larger than thefirst threshold value are set in advance according to, for example, theshape of the pattern on the substrate to be processed such as theroughness. In an example, the first threshold value is set to an upperlimit value at which the roughness of the pattern on the substrate maybe flattened by the CVD, and the second threshold value is set to alower limit value at which the roughness of the pattern on the substratemay be flattened by the ALD. Next, before a processing is performed orafter a processing is performed a predetermined number of times, theshape of the pattern on the substrate to be processed such as theroughness is measured, and the measured value is compared with the firstthreshold value and the second threshold value. When the measured valueis equal to or less than the first threshold value, the CVD is selectedas the film formation processing. When the measured value is larger thanthe first threshold value and less than the second threshold value, themix mode described above is selected as the film formation processing.When the measured value is equal to or larger than the second thresholdvalue, the ALD is selected as the film formation processing. Then, theroughness of the pattern on the substrate is improved by the selectedfilm formation processing.

Referring back to FIG. 12 , descriptions of the substrate processingapparatus 100A according to the second embodiment will be continued. Thecontroller 120 A includes the acquisition unit 123, in addition to theselection unit 121 and the instruction unit 122 which are similar tothose in the first embodiment.

The acquisition unit 123 acquires the measured value from the measuringapparatus 300 or the like through the input unit 130 and/or thecommunication unit 150. The measured value that is acquired by theacquisition unit 123 includes the above-described aspect ratio and powerspectral density.

FIG. 15 is a flowchart illustrating an example of the flow of thesubstrate processing method according to the second embodiment. First,the acquisition unit 123 acquires the measured value of the patternformed on the substrate to be processed (step S21). Further, theacquisition unit 123 acquires a target value of a pattern to be formedon the substrate to be processed, for example, Device ID. Subsequently,the selection unit 121 refers to the association storage unit 113, andselects a processing that corresponds to the target value and themeasured value that have been acquired (step S22). The selection unit121 sends the selected processing to the instruction unit 122. Theinstruction unit 122 instructs the processing apparatus 200 to perform aprocessing based on the processing received from the selection unit 121(step S23). Then, the processing ends.

The substrate processing apparatuses 100 and 100A may repeatedly performthe processing described above on one substrate. For example, thesubstrate processing apparatuses 100 and 100A may select and perform thenext processing each time the performance of the current processing iscompleted.

In the second embodiment, the association table stored in theassociation storage unit 113 may be appropriately updated according tothe processing result in the processing apparatus 200. For example, themeasuring apparatus 100 may acquire measured values that represent theshape of the pattern on the substrate before and after a processing. Forexample, the measuring apparatus 300 may measure the state of thepattern on the substrate each time a processing ends in the processingapparatus 200, and transmit the measured value to the substrateprocessing apparatus 100 A. Then, the substrate processing apparatus100A may update the association table according to a difference betweenthe measured value after the processing and the target value. Further,the substrate processing apparatus 100A may generate the associationtable by a machine learning based on the measured values of the patternon the substrate before and after the performance of a processing, andthe target value.

(Effects of Second Embodiment)

As described above, the substrate processing method according to thesecond embodiment includes the step of measuring the value thatrepresents the shape of the pattern on the substrate surface before aprocessing is performed, and the step of selecting a processingcondition based on the measured value. The processing is performed underthe selected processing condition. For example, the substrate processingapparatus performs the purging step under selected processing condition.As a result, according to the second embodiment, the substrateprocessing apparatus may select a processing to be performed accordingto the shape of the pattern on the substrate. Thus, the substrateprocessing apparatus may select and perform the processing thatimplements the coverage in accordance with the state of the pattern onthe substrate.

The substrate processing method according to the second embodiment mayinclude the step of measuring the value that represents the shape of thepattern on the substrate surface after a processing is performed apredetermined number of times. The substrate processing method accordingto the second embodiment may include the step of selecting a processingcondition for a processing to be subsequently performed, based on thedifference between the measured value before the processing is performedand the measured value after the processing is performed a predeterminednumber of times. As a result, according to the second embodiment, thenext processing may be selected after the processing performance isevaluated.

The substrate processing method of the second embodiment may alsofurther include the step of etching the substrate using the film formedon the surface of the substrate as a mask (protective film), andrepeatedly perform the film formation and the etching two or more times.In this case, the film formation and the etching may be performed in thesame chamber or in different chambers.

(Example of Processing Apparatus 200 according to Embodiment)

FIG. 16 is a view illustrating an example of a configuration of theprocessing apparatus 200 in which the substrate processing according tothe first and second embodiments is performed. FIG. 16 illustrates aschematic cross section of the processing apparatus 200. The processingapparatus 200 illustrated in FIG. 16 is a parallel flat plate typeplasma processing apparatus. The processing apparatus capable ofperforming the substrate processing of the first and second embodimentsis not limited to the processing apparatus illustrated in FIG. 16 .

The processing apparatus 200 includes a chamber 12 that is airtightlyconfigured. The chamber 12 has a substantially cylindrical shape, anddefines a processing space S where plasma is generated, as an internalspace thereof. The processing apparatus 200 includes a stage 13 insidethe chamber 12. The upper surface of the stage 13 is formed as aplacement surface 54 d on which a wafer W to be processed is placed. Inthe present embodiment, the stage 13 includes a base 14 and anelectrostatic chuck 50. The base 14 has a substantially disc shape, andis provided at a lower portion of the processing space S. The base 14 ismade of, for example, aluminum and has a function of a lower electrode.

The electrostatic chuck 50 is provided on the upper surface of the base14. The electrostatic chuck 50 has a disc shape with a flat uppersurface, and the upper surface corresponds to the placement surface 54 don which the wafer W is placed. The electrostatic chuck 50 has anelectrode 54 a and an insulator 54 b. The electrode 54 a is providedinside the insulator 54 b, and a DC power supply 56 is connected to theelectrode 54 a via a switch SW. When a DC voltage is applied to theelectrode 54 a from the DC power supply 56, a Coulomb force isgenerated, and the wafer W is adsorbed and held on the electrostaticchuck 50 by the Coulomb force. Further, the electrostatic chuck 50includes a heater 54 c inside the insulator 54 b. The heater 54 c heatsthe electrostatic chuck 50 in the manner that a power is supplied from apower feeding mechanism (not illustrated) to the heater 54 c. As aresult, the temperatures of the stage 13 and the wafer W are controlled.

In the present embodiment, the processing apparatus 200 further includesa tubular holder 16 and a tubular support 17. The tubular holder 16 isin contact with the lateral surface and the edge of the bottom surfaceof the base 14, to hold the base 14. The tubular support 17 extendsvertically from the bottom of the chamber 12, and supports the base 14via the tubular holder 16.

A focus ring 18 is provided on the edge of the upper surface of the base14. The focus ring 18 is a member for improving the in-plane uniformityof the processing accuracy of the wafer W. The focus ring 18 is aplate-shaped member having a substantially ring shape, and is made of,for example, silicon, quartz, or silicon carbide.

In the present embodiment, an exhaust passage 20 is formed between theside wall of the chamber 12 and the tubular support 17. A baffle plate22 is attached to the entrance of the exhaust passage 20 or in themiddle thereof. An exhaust port 24 is formed at the bottom of theexhaust passage 20. The exhaust port 24 is defined by an exhaust pipe 28fitted into the bottom of the chamber 12. An exhaust device 26 isconnected to the exhaust pipe 28. The exhaust device 26 has a vacuumpump, and by operating the vacuum pump, the processing space S insidethe chamber 12 may be depressurized to a predetermined degree of vacuum.As a result, the processing space S inside the chamber 12 is maintainedin a vacuum atmosphere. The processing space S is an example of a vacuumspace. A gate valve 30 is attached to the side wall of the chamber 12 toopen/close the carry in/out port of the wafer W.

A radio-frequency power supply 32 is electrically connected to the base14 via a matching unit 34. The radio-frequency power supply 32 is apower supply for generating plasma, and applies a radio-frequency powerof a predetermined frequency (e.g., 13 MHz) to the lower electrode, thatis, the base 14. A refrigerant flow path (not illustrated) is formedinside the base 14, and the processing apparatus 200 circulates arefrigerant in the refrigerant flow path so as to cool the stage 13. Asa result, the temperatures of the stage 13 and the wafer W arecontrolled.

The processing apparatus 200 further includes a shower head 38 in thechamber 12. The shower head 38 is provided at the upper portion of theprocessing space S. The shower head 38 includes an electrode plate 40and an electrode support 42.

The electrode plate 40 is a conductive plate having a substantially discshape, and makes up an upper electrode. A radio-frequency power supply35 is electrically connected to the electrode plate 40 via a matchingunit 36. The radio-frequency power supply 35 is a power supply forgenerating plasma, and applies a radio-frequency power of apredetermined frequency (e.g., 60 MHz) to the electrode plate 40. Whenthe radio-frequency power supply 32 and the radio-frequency power supply35 apply the radio-frequency power to the base 14 and the electrodeplate 40, respectively, a radio-frequency electric field is formed inthe space between the base 14 and the electrode plate 40, that is, inthe processing space S.

A plurality of gas vent holes 40 h is formed in the electrode plate 40.The electrode plate 40 is detachably supported by the electrode support42. A buffer chamber 42 a is provided inside the electrode support 42.The processing apparatus 200 further includes a gas supply 44, and thegas supply 44 is connected to a gas inlet port 25 of the buffer chamber42 a via a gas supply conduit 46. The gas supply 44 supplies aprocessing gas into the processing space S. The processing gas may be,for example, a processing gas for the etching or the film formation. Aplurality of holes is formed in the electrode support 42 to becontinuous to the plurality of gas vent holes 40 h, respectively, andcommunicate with the buffer chamber 42 a. The gas supplied from the gassupply 44 is supplied into the processing space S via the buffer chamber42 a and the gas vent holes 40 h.

In the present embodiment, a magnetic field forming mechanism 48 isprovided in the ceiling portion of the chamber 12 to extend in anannular shape or concentrically. The magnetic field forming mechanism 48functions to facilitate the start of the injection of the radiofrequency (plasma ignition) in the processing space S, and maintain theinjection stably.

In the present embodiment, the processing apparatus 200 further includesa gas supply line 58 and a heat transfer gas supply 62. The heattransfer gas supply 62 is connected to the gas supply line 58. The gassupply line 58 extends to the upper surface of the electrostatic chuck50, and extends in an annular shape in the upper surface of theelectrostatic chuck 50. The heat transfer gas supply 62 supplies a heattransfer gas such as, for example, He gas between the upper surface ofthe electrostatic chuck 50 and the wafer W.

The controller 90 comprehensively controls the operation of theprocessing apparatus 200 configured as described above. The controller90 includes a process controller 91 provided with a central processingunit (CPU) to control each unit of the processing apparatus 200, a userinterface 92, and a storage unit 93. In the present embodiment, thecontroller 90 may be provided inside the substrate processingapparatuses 100 and 100A.

The user interface 92 is configured by, for example, a keyboard withwhich a process manager performs an operation to input commands formanaging the processing apparatus 200, or a display that visualizes anddisplays the operation status of the processing apparatus 200.

The storage unit 93 stores control programs (software) for implementingvarious types of processing performed in the processing apparatus 200under the control of the process controller 91, and a recipe thatstores, for example, processing condition data. Then, when an arbitraryrecipe is retrieved from the storage unit 93 by, for example, aninstruction from the user interface 92 and executed by the processcontroller 91 as necessary, a desired processing is implemented in theprocessing apparatus 200 under the control of the process controller 91.The control programs or the recipe such as processing condition data maybe stored in a computer-readable storage medium (e.g., a hard disk, aCD, a flexible disk or a semiconductor memory).

Further, the control programs or the recipe such as processing conditiondata may be used online by being transmitted from another device at anytime through, for example, a dedicated line.

FIG. 17 is a view illustrating an example of a processing system whichis usable for performing the substrate processing according to the firstand second embodiments.

A processing system 1000 illustrated in FIG. 17 includes a controllerCnt, mounts 1122 a, 1122 b, 1122 c, and 1122 d, accommodation containers1124 a, 1124 b, 1124 c, and 1124 d, a loader module LM, and load lockchambers LL1 and LL2, a transfer chamber 1121, and a plasma processingapparatus 1010. The plasma processing apparatus 1010 may be, forexample, the processing apparatus 200 illustrated in FIG. 16 .

The controller Cnt is a computer provided with, for example, aprocessor, a storage unit, an input device, and a display device, andcontrols each unit of the processing system 1000 to be described later.The controller Cnt is connected to, for example, transfer robots Rb1 andRb2, an optical observation device OC, the plasma processing apparatus1010. The controller Cnt may also serve as the controllers 120 and 120Aof the substrate processing apparatuses 100 and 100A illustrated inFIGS. 7 and 12 and the controller 90 of the processing apparatus 200illustrated in FIG. 16 . Further, the controller Cnt may be thesubstrate processing apparatus 100 or 100A.

The controller Cnt operates according to a computer program (a programbased on an input recipe) for controlling each unit of the processingsystem 1000, and sends out a control signal. The respective units of theprocessing system 1000, for example, the transfer robots Rb1 and Rb2,the optical observation device OC, and each unit of the plasmaprocessing apparatus 1010 are controlled by the control signal from thecontroller Cnt. In the plasma processing apparatus 1010, the selectionand the flow rate of a gas from the gas supply 44, the exhaust of theexhaust device 26, the supply of power from the radio-frequency powersupplies 32 and 35, the supply of power to the heater 54 c, and the flowrate and the temperature of the refrigerant may be controlled by thecontrol signal from the controller Cnt. Each step of the substrateprocessing method according to the first and second embodiments may beperformed by operating each unit of the processing system 1000 under thecontrol of the controller Cnt. The storage unit of the controller Cntstores a computer program for executing the substrate processing methodaccording to the first and second embodiments, and various data used forthe execution, in a freely readable manner.

The mounts 1122 a to 1122 d are arranged along one edge of the loadermodule LM. The accommodation containers 1124 a to 1124 d are provided onthe mounts 1122 a to 1122 d, respectively. The wafer W may beaccommodated in each of the accommodation containers 1124 a to 1124 d.

The transfer robot Rb1 is provided inside the loader module LM. Thetransfer robot Rb1 takes out the wafer W accommodated in any one of theaccommodation containers 1124 a to 1124 d, and transfers the wafer W tothe load lock chamber LL1 or LL2.

The load lock chambers LL1 and LL2 are provided along the other edge ofthe loader module LM, and connected to the loader module LM. The loadlock chambers LL1 and LL2 make up preliminary decompression chambers.Each of the load lock chambers LL1 and LL2 is connected to the transferchamber 1121.

The transfer chamber 1121 is a chamber that may be depressurized, andthe transfer robot Rb2 is provided inside the transfer chamber 1121. Theplasma processing apparatus 1010 is connected to the transfer chamber1121. The transfer robot Rb2 takes out the wafer W from the load lockchamber LL1 or LL2, and transfers the wafer W to the plasma processingapparatus 1010.

The processing system 1000 includes the optical observation device OC.The wafer W may be moved between the optical observation device OC andthe plasma processing apparatus 1010 by the transfer robots Rb1 and Rb2.After the wafer W is accommodated in the optical observation device OCby the transfer robot Rb1 and aligned inside the optical observationdevice OC, the optical observation device OC measures the trench widthof the pattern such as the mask of the wafer W, and transmits themeasurement result to the controller Cnt. The optical observation deviceOC may measure trench widths of patterns such as masks formed in aplurality of regions of the surface of the wafer W. The measurementresult obtained by the optical observation device OC is used as, forexample, the “measured value” in the second embodiment (see FIG. 15 ).

According to the present disclosure, the coverage of a film formed on asubstrate may be continuously controlled.

From the foregoing, it will be appreciated that various embodiments ofthe present disclosure have been described herein for purposes ofillustration, and that various modifications may be made withoutdeparting from the scope and spirit of the present disclosure.Accordingly, the various embodiments disclosed herein are not intendedto be limiting, with the true scope and spirit being indicated by thefollowing claims.

What is claimed is:
 1. A method for processing a substrate comprising:(a) exposing a substrate with a pattern formed on a surface thereof to afirst reactive species in a chamber, thereby adsorbing the firstreactive species onto the surface of the substrate; (b) exposing thesubstrate to plasma formed by a second reactive species in the chamber,thereby forming a film on the surface of the substrate; and (c)repeating a processing including (a) and (b) two or more times whilechanging a residence amount of the first reactive species at a time ofstarting (b).
 2. The method according to claim 1, wherein the residenceamount of the first reactive species at the time of starting (b) ischanged by controlling an amount of the first reactive speciesintroduced into the chamber in (a).
 3. The method according to claim 1,wherein the residence amount of the first reactive species at the timeof starting (b) is changed by controlling a dilution degree of the firstreactive species introduced into the chamber in (a).
 4. The methodaccording to claim 1, wherein (a) includes: (a1) introducing the firstreactive species into the chamber; and (a2) purging at least a portionof the first reactive species from the chamber.
 5. The method accordingto claim 4, wherein the residence amount of the first reactive speciesat the time of starting (b) is changed by controlling an amount of thefirst reactive species purged in (a2).
 6. The method according to claim5, wherein the residence amount of the first reactive species at thetime of starting (b) is changed by controlling the amount of the firstreactive species purged in (a2) in a manner of changing at least one ofa pressure in the chamber, a purging time, and a flow rate of a purgegas.
 7. The method according to claim 1, wherein (a) or (b) isterminated before a reaction on the surface of the substrate issaturated.
 8. The method according to claim 1, wherein the residenceamount of the first reactive species at the time of starting (b) iscontrolled to make a thickness of a film formed on an upper portion ofthe pattern larger than a thickness of a film formed on a lower portionof the pattern.
 9. The method according to claim 1, wherein theresidence amount of the first reactive species at the time of starting(b) is controlled to make a thickness of a film formed on an upperportion of the pattern similar to a thickness of a film formed on alower portion of the pattern.
 10. The method according to claim 1,further comprising: (d) etching the substrate using the film formed in(c) as a mask.
 11. The method according to claim 10, further comprising:(e) repeating a processing including (c) and (d) two or more times. 12.The method according to claim 1, further comprising: measuring a valuethat represents a shape of the pattern on the surface of the substratebefore (a) is performed; and selecting a processing condition based onthe measured value, wherein (a), (b), and (c) are performed under theprocessing condition selected in the selecting.
 13. The method accordingto claim 12, further comprising: measuring a value that represents theshape of the pattern on the surface of the substrate after (c) isperformed a predetermined number of times; and selecting a processingcondition for a processing to be subsequently performed, based on adifference between the value measured before (a) is performed and thevalue measured after (c) is performed a predetermined number of times.14. The method according to claim 1, wherein (c) is repeatedly performeduntil the shape of the pattern satisfies a predetermined condition. 15.The method according to claim 1, wherein (c) is performed in a samechamber.
 16. The method according to claim 1, wherein (c) is performedby setting the pressure in the chamber to about 10 mTorr to about 200mTorr.
 17. A method for processing a substrate comprising: measuring avalue that represents a shape of a pattern on a surface of thesubstrate; comparing the value with a first threshold value and a secondthreshold value larger than the first threshold value, which are set inadvance; selecting a film formation processing based on a result of thecomparing; and forming a film on the surface of the substrate accordingto the film formation processing selected in the selecting, whereinselecting a film formation processing includes: selects a chemical vapordeposition (CVD) as the film formation processing when the value isequal to or smaller than the first threshold value, selects a mix modeas the film formation processing when the value is larger than the firstthreshold value and smaller than the second threshold value, and selectsan atomic layer deposition (ALD) as the film formation processing whenthe value is equal to or larger than the second threshold value, andwherein the mix mode includes: (a) exposing the substrate with a patternformed on a surface thereof to a first reactive species in a chamber,thereby adsorbing the first reactive species onto the surface of thesubstrate; (b) exposing the substrate to plasma formed by a secondreactive species in the chamber, thereby forming a film on the surfaceof the substrate; and (c) repeating a processing including (a) and (b)two or more times while changing a residence amount of the firstreactive species at a time of starting (b).
 18. An apparatus forprocessing a substrate, comprising: a chamber including a gas inlet anda gas outlet; a plasma generator configured to generate plasma in thechamber; and a controller configured to control an overall operation ofthe apparatus for processing the substrate and programmed to: (a) exposethe substrate with a pattern formed on a surface thereof to a firstreactive species in the chamber, thereby adsorbing the first reactivespecies onto the surface of the substrate; (b) expose the substrate tothe plasma generated by the plasma generator and formed by a secondreactive species in the chamber, thereby forming a film on the surfaceof the substrate; and (c) repeat a processing including (a) and (b) twoor more times while changing a residence amount of the first reactivespecies at a time of starting (b).